HT9170D-18SOPLF (HOLTEK)

The HT9170D-18SOPLF is a DTMF (Dual Tone Multi Frequency) receiver in 18 pin SOP package. This receiver has integrated digital decoder, bandsplit filter function as well as power down mode and inhibit mode operations. It uses digital counting techniques to detect and decode all 16 DTMF tone pairs into 4bit code output. Highly accurate switched capacitor filters are implemented to divide tone signals into low and high group signals. A built-in dial tone rejection circuit is provided to eliminate need for prefiltering.